Method of separating metal from metalliferous material



Patented Mgr. 3o, 1926.

LELAND wEMrLE, or CLEVELAND, omo.

METHOD or4 sErAn'a'rrNG METALrRoM METALLIFEnoUs MATERIAL.

Application mea November 1e, 1923. seria No. 675,028.

To all whom it 01mg/ concern Be it known that I, LELAND E. VEMPLE, a citizen of the United States, and resident of the city of Cleveland, county of Cuyahoga, State of Ohio, have invented certain new 1nd useful Improvements in Methods of SeparatingMetal from Metalliferous Material, of which the following is a specification.

My invention relates generally to the art oflsmelting metalliferous material and particularly ores of such metals as zinc, antimony, cadmium and the like, which in'their oxid form constitute a directly usable commercial material. The object of this invention is to produce such metal oxids in a single operation .and to accomplish this valong lines which are simple, convenient, ef-

. ficient and economical.

l ten and fall from the stream of gas, Whereasl The invention, speaking generally, resides in causing the separation of the metal from the other constituents of the metalliferous materialk to take lace while such material is in a. state o extremely tine division andwhile. its particles are in motion suspended in a gaseous environment.. If dealt 'with in this Way, the metals become volatilized, in the form of a fume, either as metals orl as combinations ofthe metals, for example, oxides and sulfates, While the non-metallic parts of the material remain solid or molthe volatilized metal or metal combination upon .cooling and 1n association with accompanying air 1s recovered 1n a form vvhlch renders it directly available as a completely' manufactured commercial' article.'

Heretofore the processes for treatlng ores 'for the recovery of volatile metals in the form of pigments or .in the'form of a concentrated fume product, as from low-grade Oores and metalhferousmaterlals have been generally predicated upon the conception that the metal-,bearing material should be of a. relatively coarse size, say one-eighth of an inch to one inch or more in diameter. These processes provide for the blowing of a blast of air through a bed or column composed or ore, reduction fuel and fluxcalled the charge, and this charge is supported'on a suitably perforated grate in a relatively thin bed, or, when supported onitself in a thicker column, the charge consists of large pieces Ahaving a relatively slow melting rate 1n or' der that the column may remain porous to y Y separated out of the stream while 'the roducts Yof volatilization' are carried o by' the air blast until the volatile materials are reduced and driven 0H. Itis thus necessary throughout the charge.

resort has been had to an artificial coarsening to the successful operation of such processes that the charge shall consist of relatively coarse lumps fwhich, when superimposed, yield interstitial spaces through which the forced air blast shall pass .'freely. Attempts to treat fine ores or to use fine sized reductlon fuels and lux`by any such processes have proved unsuccessful as the charge is too com- -pact and the passage of air so impeded that the smelting temperatures are notobtained In some lnstances of the ore, fueland flux before they :treintrodi'iced into a charfreor to an enlargement of the particles ol' the charge itself by means of a preliminary treatment consisting of briquetting or nodulizing the materials into the desired size. Such 'preliminary treatments add greatly. to the cost of the -entire smelting operation and in some` cases the brquetted lumps melt or disintegrate in the smeltirig furnace before the metal content of the charge is completely driven off. This inefficiency and the added expense `)render the smelting of-someores or metalliferous materials by .the known processes uncommercial.

. According to the process of this application the reduced size of theV ore particles is no longer a disadvantagabut, on the ccn- -trary, the finer these materials are lobtainable, the more satisfactory Will be the operation of my process.- According to the new process satisfactory results will'be obtained if all of the materials composing a charge4 are reduced to a size which Will permit them to pass through a; screen having approximatelyV 200 mesh 'per square inch. These materials in this conditionofline d ivision are mixed in v suitable proportions changes in temperature and by properly directing thef flow ofthe products of the smelting reactions, those products .-whlch are nonvolatile Will be thrown down and means of the forced draft to more distant points, where they are cooled and passed through collectingl devices which (for eX- vample by filtration) separate and collect the volatilized metalliferous materials in the form of a fume and allow those products p of the smelting which remain gaseous at A. 1 there is a hopper 6 containing the charge.

' furnace.

relatively low temperatures to pass through and escape. ,l Thev invention may be carried out in the apparatus illustrated in the accompanying drawing in which'Fig. 1` is a diagrammatic sectional elevation of the furnace, Fig. 2 a

horizontal section of the furnacevv shown in Fig. 1 and Fig. 3 a cross section of said In the drawing 1 indicates the furnace and 2 baffles therein. to forma sinuous passage forthe gases, fumes, etc., 3 is the exit conduit, 4 the suction fan, 5- the collecting device, for instance filtering bags for the product. At one end of the `furnace This charge, as stated, consists of material vusually comprising in addition to the ore or other metalliferous substance to be treated, reduction fuel and fluxing materialf. These constituents of the charge, if not received from tli'e mnesor other source of supply in a size sufficiently small to pass throughja 200 mesh fare first dried and groundto that Asize and then mixed in the proper proportion. f The proportion will obviously be different to meet varying conditions, but generally the proportions are those which are employed where the smelt- 'ingp of coarser particles (of the same chemical composition) as heretofore described has been conducted. In the case of zinc ores the "mixtiire may vary from4 equal parts to two or more'parts of fuel to one part of ore, depending upon the grade'f -theore and fuel and in certain cases there isalso addedtothis mixture a quantity of flux,

for example, 20% to 10% limestone also ground to the proper-size. This mixture thus prepared is stored in suitable bins adxjacent to or overhead the furnace or retort in order that it may be fed bygravity. lFor' the purpose of illustration, 'th'echarge has been shown as stored in the `hopper 6 from which it enters the burner or atomizer 7.

This burnerv maybe of any suitable design capable of delivering. a' char e of'this charac ter linto the furnace in anely dispersed or atomized condition by -mean of air, steam, gas or other agent introdu vat 8.

A A `satisfactory burner consists of a piece of steel pipe 9 about three feet -long and four'inches in diameter, the outer end closed with a bushing through which passes a two inch steel pipe 10,'A terminating about six inches from fthel mouth ofthe four inch Va supplyv of compressed airthe pressure of..

pipe; The two inch pipe iseonnected with which i'sreaulatad bysutablavalves. about y through whic other parts, such as 15.

burner 7 i ten inches from thev outer end of the four inch pipe 9 there'is an upper in-take opening of' about three inches diameter' with which the ipe 11 Icommunicates and the charge enters. A slide gate 12 in Ythis in-take pipe 11 regulates the quantity .of dhargcr entering the burner.

The burner -7 is set inthe front Wall of the furnace at about threevfourths of tle height ofthe furnace and the inner end of the burner is approximately flush with the `inner side of the wall of the furnace.

lov

Compressed air is generally turned on first at a pressure which it will give it a high velocity and induce a' strong suction. The gate 12 of the charge in-take is then opened and the charge drawn into pi e 9 and dis charged into the furnace at igh velocity and in finely dispersed condition. lVithin the furnace there prevails'a condition of heat adequate to the process vsupplied through an oil-air burner 13 and supplemental burners 14. lVhe'n the charge is atomized into the furnace, it becomes igf vparts of the ore or other metalliferous material to accumulate for'. ready removal through the door 17. The furnace may be of variable gdimensidns, depending on the quantity of charge smelted per minpte and the smelting temperature required. For thel treatment of zinc ore charge of the described characteristics` at the rate of one hundred and 'fifty' pounds per minute requiring a smelting temperature of about 2500CJ I prefer to use a furnace constructed of fire brick, suitably braced, having inside dimensions afv about four feet width, six feet height and forty feet length. -At the exit end of the furnace isa steel' cooling pipe 18 about twenty-four inches diameter and It has been found that a fabout six hundred feet in length. For the first ten feet the furnace adjacent to the s -unobstructed andr formsthe laboratol l f9 in which the primary smelt-A ing reactions take place The auxiliary burners 14 which may be adapted for consuming gas, oil or powdered coal or other fuel are installed at the sides of the labora tory chamber to the proper temperature to` ignite ythe charge andto maintam smeltingl reactions. After the laboratory 19 hasbeen heated t9 the proper degreeLtlieseauzglhary 19 for the purpose of heating this izo burners may be shut oi in 'part or entirely and vthe burner 13- may be similarly operated and controlled. The laboratory 19 is terminated 4b one of the baffle walls 2 which extents from bottom to top and from one side to within. about ten inches of the opposite side of the furnace. The remaining thirty feet of the furnace` has similar baliie walls placed .about every six feet apart but in alternate and opposite directions, thus producing not only a sel ies of bafiie for 'the products of smelting to strike against, but also giving --repeated changes in the' directionvof flow. By these n means liquid and solid non-volatile productsare caused to settle out and to fall to the-bottom ofl the furnace Where they areJ removed fronrtime to time through suitable doors 17. The temperature ofthe entire furnace is maintained at a degree which prevents the volatile metalcompounds-from.

depositing with the non-volatile vmatter.

The suction fan 4 provides a 'draft through" the furnace which carries the fume IJand gases through the coolingpipe 18. f To collect any small 'quantities of non-volatile products which lmay be entrained into the cooling-pipe 1 8, I prefer to instal cyclone settlers at its cooler end. By a proper adjustment of the draft practically all of the fume is drawn out of the furnace through the cooling pipe 18 andfifiltdered -througha series of cloth bags 5 linto which the suction fan 4 discharges through 'suitable pipes.

The operation of the bag filters isI similar against the first one), the tendency in eitherA case being to eject such matter from the gas stream carrying the fumesv of metal com pounds. This ejectingetfect -vis repeated as the gases find their ai'ay through the passages formed byl th' partitions 2. AThe entire smelting pperationis thus performed on an ore or other metalliferous substance which at thetime of smelting is a floating particleof diminutive size. The HVolatile metals or compounds which are redueed-by the treatment in the furnace usually com? bine with oxygen to form chiefly 'metal oxides. Ihe recovery or product is thus zinc oxid (in thosecases vvher'e zinc ore is used as the starting material) and is in a form and condition `Where it is directly available for sale and use.A

I donot claim to be the first to have performed a chemical reaction'on material exposed in a-stalte of fine division to heat and to co-acting chemical matter While the chemical under treatment is suspended in a gaseous atmosphere', but I do claim that I ainthe first tp conduct a smelting operation with extremely fine particles of Aore 0r other meta1liferous-material and to 'effect the yseparation of themetallic values from uch ores or other metalliferous material during flotation or suspension in a gaseous environment. f.

I claim: A process, which comprises blasting into 4a heated furnace chamber, a mixture, of-

metalliferous material containing'a volatilizable metal,l soliti carbonaceous' fuel and flux, the ingredients being in proportions suiiicient to'v Wholly reduce the metallifer'- ous material, l'falso maintaining heating means in said chamber, separate from the blast rof said mixture kof fuel, flux and metalliferous material'and thereby maintaining in said chamber a ltemperature high enough to vaporize substantially all of said vaporizable metal, causing the vapori'zed and fumed .material to travel through a tortu'us passage, while` hot and 4while'maiutaining oxidizing conditions therein during' a part at least of said travel, and thereafter collecting the oxidized vaporizable metal, "substantiallyfree from slag.

vIn testimony whereof I have' hereunto set m hand. 'l y LELAND E. WEMPLE. 

